CPT 00400: Anesthesia for Integumentary Procedures on Extremities, Trunk, Perineum
CPT code 00400 designates anesthesia services for procedures on the integumentary system of the extremities, anterior trunk, and perineum when no more specific anesthesia code applies. This code is used across ambulatory surgery centers, hospital operating rooms, and procedure suites for a wide range of dermatologic and soft-tissue interventions. Nationally, accurate use of this anesthesia code supports correct payment, quality reporting, and aggregation of anesthesia utilization for common integumentary procedures.
Key payers addressed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication summarizes payer coverage considerations, common clinical contexts that generate use of this code, and how it relates to adjacent anesthesia codes for integumentary procedures. Readers will find a concise clinical description, expected sites of service, common diagnoses that generate billing (for example, skin infections, abscess drainage, abrasions, and open wounds), and crosswalks to related anesthesia codes for breast and other integumentary procedures.
This briefing is designed for billing managers, anesthesia clinicians, and policy analysts seeking a clear reference on when CPT code 00400 applies, which payers commonly encounter it, and how it fits into the broader set of anesthesia codes for integumentary system procedures.
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Billing Code Overview
CPT code 00400 describes anesthesia services for procedures on the integumentary system involving the extremities, anterior trunk, and perineum. The code applies when the anesthesia provider performs services for any surgical or procedural intervention on these anatomical regions that is not otherwise specified by a more specific anesthesia code.
Service type: Anesthesia for integumentary procedures
Typical site of service: Operating room or procedure suite for dermatologic, soft-tissue, or minor surgical procedures on the extremities, anterior trunk, or perineal region
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult presenting to the ambulatory surgical center or hospital minor procedures unit with a localized skin or soft-tissue lesion on an extremity or anterior trunk requiring incision and drainage, excision, debridement, or repair. Examples include a cutaneous abscess of the forearm, cellulitis with focal drainage and washout of the lower leg, an abrasion of the knee requiring wound exploration and closure, or an open ankle wound requiring irrigation and debridement. The anesthesiology team (Anesthesiology Physician, Certified Registered Nurse Anesthetist, or Anesthesiology Assistant) evaluates the patient preoperatively, documents airway and ASA physical status, and selects an appropriate anesthetic technique such as general anesthesia, monitored anesthesia care (MAC), or regional block depending on procedure complexity, patient comorbidity, and patient preference.
Perioperative workflow: pre-anesthesia assessment and consent; induction of anesthesia in pre-op or OR; intraoperative monitoring and anesthetic management during integumentary procedure on extremity, anterior trunk, or perineum; emergence and handoff to PACU nursing with postoperative anesthesia record and pain control plan. Documentation includes start and stop times for anesthesia, airway management, medications administered, monitoring events, and any intraoperative complications that may affect coding or modifier selection.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | When anesthesia care required substantially greater time, technical difficulty, or intensity beyond typical for the procedure and supported by documentation |
| 23 | Unusual anesthesia | When general anesthesia is administered for a procedure that normally does not require it, with documentation of medical necessity
| 50 | Bilateral procedure | When identical integumentary procedures are performed on both sides of the body in the same session
| 52 | Reduced services | When the procedure is partially reduced or not completed as planned and documentation supports decreased service
| 53 | Discontinued procedure | When the procedure is terminated due to extenuating circumstances or patient safety before completion
| 56 | Preoperative assessment only | When only pre-anesthetic evaluation is provided and intraoperative anesthesia services are not performed
| 59 | Distinct procedural service | When a separate, distinct procedural service is performed that is not normally bundled with the primary procedure
| 62 | Two surgeons | When two surgeons work together as primary surgeons, relevant if anesthesia time and complexity are affected
| 78 | Unplanned return to OR following initial procedure | When the patient returns to the operating room for related procedure during the postoperative period
| AA | Anesthesia by anesthesiologist | When an anesthesiologist personally performs the anesthesia service
| AD | Medical supervision by a physician; more than four concurrent anesthesia procedures | When a physician supervises multiple concurrent anesthesia providers per payer rules
| AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for anesthesia | When these providers perform or assist in anesthesia services per state and payer policy
| LT | Left side | To identify laterality for procedures performed on the left extremity
| RT | Right side | To identify laterality for procedures performed on the right extremity
| QS | Monitored anesthesia care (MAC) service | When MAC is provided and reportable per payer policy
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207L00000X | Anesthesiology Physician | Physician credential for medical direction or personal performance of anesthesia |
| 367500000X | Certified Registered Nurse Anesthetist | CRNA credential for independent or medically directed anesthesia services
| 207RA0401X | Anesthesiology Assistant | Anesthesia assistant credential for medically directed anesthesia care
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
L03.90 | Cellulitis, unspecified | Represents localized skin and subcutaneous infection often requiring incision, drainage, or debridement under anesthesia for severe or extensive cases |
| L02.91 | Cutaneous abscess, unspecified | Directly aligns with procedures such as incision and drainage of abscesses on extremities or trunk performed under anesthesia
| L98.9 | Disorder of the skin and subcutaneous tissue, unspecified | Used when a specific skin/subcutaneous disorder is not further specified but surgical management on integumentary tissue is performed
| S80.811A | Abrasion, right knee, initial encounter | Trauma-related superficial skin injury that may require wound exploration, cleansing, or closure under anesthesia in selected cases
| S91.001A | Open wound of right ankle, initial encounter | Open traumatic wound of an extremity that may need operative irrigation/debridement and repair with anesthesia services
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
00402 | Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; reconstructive procedures on breast (eg, reduction or augmentation mammoplasty, muscle flaps) | Similar anatomical base code for integumentary procedures; used when breast reconstructive procedures are performed instead of extremity/trunk procedures |
| 00404 | Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; radical or modified radical procedures on breast | Related anatomic category covering more extensive breast procedures; compared for appropriate anesthesia code selection when surgical site is breast
| 00406 | Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; radical or modified radical procedures on breast with internal mammary node dissection | Related higher-complexity anesthesia code for breast procedures involving nodal dissection; relevant when considering code hierarchy for integumentary region
| 00410 | Anesthesia for procedures on the integumentary system on the extremities, anterior trunk and perineum; electrical conversion of arrhythmias | Related by anatomic modifier set; used for anesthesia services when electrical conversion of arrhythmia occurs in context of integumentary procedures